The present invention relates generally to powertrain systems, and more specifically, to internal combustion engines.
A wide variety of reciprocating and rotating internal combustion engine designs currently exist. The most common is the four-stroke reciprocating engine, such as those used with Otto and Diesel cycles. There are various disadvantages of these designs. Significant weight is required for components such as the crankshaft and deep skirt of the block. The geometry of the engine, such as the stroke and valve events, is generally fixed, which is leads to compromised performance and efficiency over the range of operating speeds. A design typically works only with a specific type of fuel. Also, the design is large and space-consuming, because the components must be placed in specific relationship to each other. There are other disadvantages not detailed here.
The present invention addresses these problems, and others. An internal combustion engine design is used that eliminates the connecting rods, crankshaft, and lower block of the engine, and replaces them with a hydraulic cylinder. The hydraulic cylinder can raise and lower the piston. High pressure fluid can be released from hydraulic cylinder when the piston acts downward on the hydraulic cylinder during a power stroke, sending the pressurized fluid to a fluid power device.
In an exemplary embodiment of the powertrain system, the engine piston mates to a hydraulic cylinder. Hydraulic valves precisely control the upward and downward movement of the hydraulic cylinder. The high pressure fluid produced by the hydraulic cylinder during a power stoke is sent to a fluid power device. One example of a fluid power device is a fluid turbine. In yet another exemplary embodiment of the present invention, the fluid turbine may be mated to an electric power generating and storing device, such as an integrated starter generator. Other advantages, features, and embodiments are described below.